Process of duplicating phonograph-records.



No. 667,662. Patented Feb. 5, I901.

T. A. EDISON.

PROCESS OF DUPLIGATING PHONOGBAPH RECORDS. (Application filed May 8, 1900.

(No Model.)

'IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII I'M!!! l W Invento;

Att'ys.

UNITED STATES PATENT OFFICE.

THOMAS A. EDISON, oE-LLEwELLYN PARK, NEW' JERSEY.

PROCESS OF DUPLICATING PHONOGRAPH-RECORDS.

SPECIFICATION forming' part of Letters Patent No. 667,662, dated February 1901. Application filed May a, 900. amino. 16,874. (No specimens.)

To all whom it may coneerni Be it known that I, THOMAS 'A. EDISON, a

citizen of the United States, residing at Llewellyn Park, county of Essex, and State of New Jersey, have invented a certain new and useful Improved Process of Duplicating Phonograph-Records, (N 0. 1,036,) of which the following is a specification.

My invention relates to an improved process for duplicating phonograph-records, and the process is of the character covered by my Patent No. 484,582, of October 18, 1892, wherein a matrix of an original record is employed as a moldfor the making of the duplicates. In the specific process described in my previous patent the matrix secured from the original record is divided longitudinally, so as to form a sectional mold in which are cast the desired duplicates. My present invention is designed specifically as an improvement on said process, and my object is to provide a process wherein the production of the duplicate records will be facilitated and wherein the character of the resulting duplicates will be improved, since the mold used is continuous on its bore.

My present process depends upon the fact that after a molten metallic soap or a mixture of soaps or other suitable material has been introduced within a mold carrying the representation of a phonographic record in relief on its bore and allowed to set a sufficient contraction of the resulting duplicate can be secured as to permit of a longitudinal separation of the duplicate from the mold, whereby a continuous mold can be employed for the carrying on of the process.

In order that my invention may be better understood, attention is directed to the accompanying drawings, forming a part of this specification, and in which- Figure l is a sectional view of a suitable apparatus for the purpose, illustrating the plunger and piston in their lowermost position; and Fig. 2, a similar view showing the same parts in their elevated positions.

In both the above views corresponding parts are represented by the same numerals of reference.

The apparatus illustrated in the figures isdesigned for the duplicating of cylindrical phonographic records, and it will be so de- In the drawings, 1 represents a suitable jar or tank of the proper dimensions and made of any desired material. Within the jar or tank 1 I place the material of which the duplicate records are to be formed and which maybe maintained in a-molten condition by the application of heat in any way-as, for

example, by a gas-tube 2, supplying a number of jets, as shown. The proper level of the molten material is indicated, and this level should be approximately maintained by the addition of fresh material from time to time within the tank as the liquid material maybe withdrawn duringthe operation. The material in the tank 1 and of which he duplicate records are to be formed may be of any suitable character; but preferably it is a metallic soap or a combination of several soaps to which has been added a material not alfected by, water, such as ceresin,whereby the resulting duplicates will be protected from the elfects of atmospheric moisture. Mounted within the tank and secured to its bottom is an open-ended cylinder 3, in which works a piston 4. A tapered core 5 is connected to or formed integrally with the piston 4., and said core is preferably hollow, so as to present a thin wall to the material, whereby the core will very quickly reach the temperature of the molten material'when it is immersed therein. A numberof openings 6 are formed in the cylinder 3, near the bottom thereof, below which openings the piston 4 passes in reaching its downward position, as shown in Fig. 1, whereby the liquid material may flow through said openings into the cylinder above the piston. Oonnectedto the core 5 is a. plunger '7, having an operatinghandle 8. The connection between the core and plunger is such aswill permit a separation of these parts, ordina'ry screw-threads being shown.

9 represents a-mold which rests within a shoulder 10, formed at the top of the cylinder, and which mold carries on its bore the representation in negative or relief ofa phonograph-record which it is desired to duplicate. This mold is preferably-obtained by .the openings 6.

the process described in my application for Letters Patent filed March 5, 1898, Serial No.

672,650, bytfirst depositing upon the original record a suitable metal in the form of an infiuitesimally-thin film by a process of vacuons deposit, by then electroplating or otherwise securing upon the film so obtained a sufficiently thick layer of the same or diflr'eran original phonograph-record a metal by a process of vacuous deposit is thatan absolutely accurate-copy in negative of such record will be produced irrespective of the fineness thereof. The mold 9 is preferably made of suflicient mass or thickness as to effectively chillthe molten material when the latter is introduced therein, as I shall explain. Carried by the upper part of the mold is an iuclosing' cap 11, which may bo -secured onto the mold and which forms a bearing for the plunger 7.

-In carrying out myimproved process with an apparatus of this type I prefer to proceed substantially as follows: Molten material being placed within the tank or jar 1 is maintained in its liquid or fluid condition by the application of heat. The mold 9, being exposed to the atmospheric temperature, is relatively cold. The plunger 7 is first depressed, so as. to force the piston 4 downwardwithin the cylinder,ejecting the liquid material from beneath it, which material passes out-through The bore of the cylinder 3 may, as shown, be slightly enlarged below the openings 6, so as to permit the piston 4 to pass beneath the same. As soon as the piston 4 passes below the openings 6 the molten or fluid material enters the cylinder above the piston, so as to fill the cylinder to the level of*the liquid in the tanker jam. Owing to 'th'e thin wall of the core 5 the latter will almost immediately reach the temperature oft'he molten material, so that said core will not chill' the latter. If a solid core is used, it will require to be immersed within or below the surface of the liquid material for a longer time to enable its'temperature to reach that of the molten mass; but with this exception the procone will be equally operative with a solid core as with a hollow core..

Assuming the hollow core to be used and that its temperature reaches that ofthe molten material almost immediately, the plunger 7 will be elevated, so as .to carry .the charge of molten material above the piston into the mold, as shown in Fig. 2, a greater or less excess of material passing above the mold into the cap 11. By employing the cap 11 it will be obvious that the level of the liquid material in the tank or jar may be varied considsurplus material ,within the capll.

erably without affecting the operation. The liquid molten material entering the mold i will engage all portions of the record formed on the bore thereof, and the materially lower.

temperature of the mold will result in the almost instantaneous chilli'ug'of the surface of the molten material therein. In order to facilitate this surface chilling of the liquid molten material entering the mold, the latter may be actually cooled by artificial means below atmospheric temperaturc-- as, for instance, by the circulation of cold water through a water-jacket surrounding the mold or by a blast of cold air equably directed to all'portions of the mold. The chilling of the surface of the molten material in the'mold results in the setting of the positive impression thus secured from the negative record. The

chilling of the molten material in the mold progresses toward the center, and any contraction in bulk will be compensated by the As soon as the material within the mold has been chilled throughout the entire thickness thereof the material with the piston, core, cap, and plunger are removed from the cylinder, and the material is allowed to cool by exposure to a cold atmosphere or by an air-blast until the solidified material has contracted away from the bore of the mold,so as topermit it to heremoved therefrom byforcin g the plunger downward. The plunger is tlienrenioved from the core, and the latter is extracted from the cast duplicate, carrying the positive record on its periphery before the material has contracted sufiiciently upon the core as to prevent this separation. Since the conductivity of heat from the material is efiected slowly, the outer surface of the molded duplicate becomes hard and set, while the inner portion thereof next to the core is still in a relatively plastic condition, so that this separation of the core can with ordinary care be readily eifected. The resulting duplicates thus secured after reach ing the normal temperature are properly dressed at the ends and are reamed internally to the proper size, being then ready for use.

With records made by my process the contraction of the material radially to separate it from the mold is accompanied by a considerable longitudinal contraction following the instant when the surface is first set by the chilling effect of the moldand progressing until the material reaches the normal tempe ature, such shrinkage being approximately one per cent. with ordinary blanks. For this reason it is desirable that the original record from which the matrix is made is formed on a phonograph or allied talking-machine having a fewer number of threads on its feedscrew'than the instrument on which the duplicates are finally used, in order that when the contraction has progressed to its finality the pitch of the record-thread on ,.the duplicate will correspond to the pitch of the feedscrew of the reprodncingmachine or approximately to that pitch, it being possible IIO.

with modern reproducingapparatus to effect a satisfactory reproduction from' a record, even when the pitch thereof diifers slightly from that of the feed-screw of the machine. The pitch of the feed-screw of themachine on which the original record is made will dilfer from the pitch of the feed-screw of, the mathe material employed. It will be of course chine on which the resulting duplicates are to be used to an extent depending upon the' coefficient of contraction of the material usedand will be determined by experiment with understood that after the mold has been removed from the cylinder and the separation of the cast duplicate is being effected there- I from a new mold and its accompanying parts the duplicate to be produced, then in making a hollow cylindrical matrix or mold from said original record, carrying the record in negative on itsbore, and in finally making duplicate records from the matrix or mold by introducing therein and engaging therewith material maintained in an abnormally high temperature, whereby the cooling of such duplicate will contract the pitch of the recordgroove, as and for the purposes set forth.

2. The process of duplicating phonographic records, which consists in securing a mold containing the record in negative. on its bore, in introducing a molten material in the mold to receive a surface impression from such record, in allowing the molten material to set, in contracting the set material, and in separating the-contracted molded material ;by a longitudinal movement, substantially as set forth.

-3. The process of duplicating phonographic records, which consists.in securing a mold havingarecord in relief in negative on its bore, in introducing amolten material in the mold around a core, in allowing the molten material to set, in contracting the set material, in removing the contractedlmaterial and the core fromthe mold, and in separating tially as set forth. I

4. The process of duplicating cylindrical phonograph-records, which consists in form-* ing a cylindrical mold with a recordin negative' on its bore, in introducing a molten ma;-

the core from the molded material, substanfte'rial in the mold to form a cylindrical dd 1 plicate,in allowing the duplicate to set, in

contracting the duplicate, and in removing thefcontracted duplicate by a direct longitudiu'al movement, substantially as set forth.

5. The process of duplicating cylindrical phonograph-records, which consists in forming a cylindrical mold having the record in negative on its bore,-in introducing molten material in the mold around a core, whereby a hollow cylindrical duplicate will be formed, in allowing the molten material to set, in contracting the molten material, and in withdrawing the contracted material from the mold by a direct longitudinal movement, substantially as set forth.

6. The process of duplicating cylindrical phonograph-records, which consists in forming a cylindrical mold carrying the record in negative on its bore, in introducing a molten ing the material to set, in contracting the material, in withdrawing the contracted material and core from the mold, and in separating the core from the resulting duplicate, substantially as set forth.

8o Y material in the mold around a core, in allow- I 7. The process of duplicating cylindrical phonograph-records, which consists in makinga cylindrical mold carrying a record in negative on its bore, and of suflicient mass to produce a chilling effect on molten material introduced therein, then in introducing within the mold a molten material, the surface of which becomes chilled by contact with the mold, then in contracting the duplicate so formed, and finally, separating the duplicatc from the mold by a direct longitudinal movement, substantially asset forth.

8. The process. of duplicating cylindrical phonograph-records, which consists in securing a mold carrying a record innegative on its bore, and of sufficient mass to produce a toe chilling effect on'molten-material introduced therein, then in introducing within the mold around a core a molten material, the surface of which is chilled by contact with the mold, thenincontracting the material, then in removing the contracted material and core from the-mold, and in finally separating the 'core from the material,substantially as set forth.-

91 The process of duplicating cylindrical phonograph-records, which consists in maintaining in a molten condition a mass of mate rial from which the d uplicates are to be made,

in sustaining-a mold over the mass of molten material, said mold carrying on its bore a r ecord in negative, inv successively elevating apart ofthe 'massof molten material into the mold,-'in allowing such'molten material Z within the nold'to set, in contracting the set material, and in withdrawing the resulting This specification signed and witnessed this 30th day of April, 1900.

, THOS. A. EDISON. Witnesses:

-J."F. RANDOLPH, FRANK: L. DYER.

--duplicate,from,the mold by a direct longitudi'nal movement, substantially as set forth. I25 

